1. Field of the Invention
The present invention relates to disk drive systems and, more particularly, to integrated spacer clamps for securing one or more disks to a hub of a spindle motor used in disk drive systems.
2. Description of Related Art
Disk drive data storage systems typically include one or more data storage disks and a spindle motor for rotating them. The spindle motor drives a spindle hub that supports the disks; and a clamp secures the disks to the hub.
In this regard, data storage disks have a central bore that receives the spindle hub. The clamp typically includes a circular or disk-shaped body and a number of screws that secure the body to the hub. As a result, disks positioned below the clamp body are secured to the hub. In addition, spacers are typically placed on both sides of each disk. For example, in a disk drive with a single disk, the arrangement comprises in series, a clamp, a spacer adjacent the clamp, a disk, a spacer on the opposite of the disk, and the hub. Any additional disk will likely have a spacer disposed on each side of it as well.
Specific examples of some prior art clamps include U.S. Pat. Nos. 5,838,516; 5,875,171; 5,777,832; 5,880,906; 5,274,517; 5,490,024; 5,528,434; and 5,790,346. Although each of these prior art clamps may have specific constructions and offer specific improvements, one common structural characteristic is that each incorporates a curved or rounded surface which comes into contact with a disk or spacer mounted over the hub of a disk drive.
The integrated spacer clamp of the present invention includes a spacer portion, eliminating the need for a separate spacer between the clamp and the adjacent disk. This integrated spacer clamp provides a construction that simplifies the overall hub arrangement, minimizing the cost of fabrication and assembly of the hub arrangement, reducing the likelihood of malfunction in the disk drive system, and providing effective and consistent performance.
In accordance with the preferred embodiment of the present invention, an integrated spacer clamp that secures one or more data storage disks to a hub includes a circular or disk-shaped clamp body having a predetermined height and defining top and bottom faces and a center bore through which a portion of the hub extends. The integrated spacer clamp also includes a spacer flange that extends outwardly of the bottom face of the clamp body, generally perpendicularly to the clamp body. A continuous neck portion or web interconnects the clamp body to the spacer flange. The spacer flange lies along edge portions of the clamp body, and the spacer flange has a height substantially greater than the height of the clamp body. The spacer flange has a flat, distal surface for contacting a data storage disk.
The clamp body has one or more securing bores that extend through the body and are spaced radially from the center bore. The clamp body also has one or more grooves formed in its top face, which extend a predetermined concentric distance adjacent an exterior edge of the body, and spaced radially outward from the securing bore or bores. The grooves distribute the force created by a securing member that extends through the securing bore and attaches to the spindle hub. A fewer number of screws can be used to secure the spacer clamp because there is an increased distance between the point of applied securing force or load (for example, at the screw heads) and the contact point between the spacer clamp and the underlying disk. This increased distance allows for greater distribution of force by the screws. Without the increased distance, using a lesser number of screws would result in unacceptable disk warp or waviness due to the extra force generated from each screw to maintain a total equal clamp load. The increased distribution of force through increasing the distance over which a force is applied is consistent with St. Venant""s principle. Also, the load transmitted from the screws to the contact point between the spacer flange and the underlying disk is further distributed because of the change in cross sectional area from larger to smaller, and then back to larger provided by the geometry of the spacer clamp. Specifically, the load induced by the screws is initially transmitted to the clamp body, then through the smaller area neck or web, and finally through the spacer flange. The load becomes concentrated along the neck or web; however, the load is then evenly distributed through the spacer flange.